The invention concerns a device for transferring a folded box from a magazine accommodating flat folded boxes to a circulating transport device while thereby simultaneously erecting same, comprising a holding device transferring and carrying the folded box during transfer, and an erecting member, wherein the holding device and the erecting member are rotatably disposed on a planetary part of a planetary gearing and are moved through a hypocycloid path having several turning points and intermediate curves, wherein the planetary part is rotatably disposed on a planetary support which rotates about a stationary sun axis.
A device of this type is used in packaging machines. Before introducing the product to be packaged, these machines must first erect the folded boxes, which are initially disposed in a magazine in flattened form, and introduce same into a transport device, which is usually a band or chain conveyor. Towards this end, each folded box is removed from the magazine by a holding device which is usually a suction device disposed on a circulating planetary part of a removal device travelling about a sun wheel, and is transported together with same along a hypocycloid path to the chain conveyor and disposed in a space defined between two carrier fingers. During movement along the hypocycloid path, an erecting member disposed on the planetary part is brought into abutment with the folded box thereby erecting it. It has turned out that use of a simple planetary gearing in the transferring device is insufficient to guarantee prolonged and proper transfer of the folded box to the chain conveyor. For this reason, attempts have been made to optimize the course of the hypocycloid path through e.g. cyclic reciprocating movement of the sun wheel or by adding a second sun wheel having a further planetary part, wherein the two sun wheels are adjustable relative to one another to thereby adjust the movements in a desired manner. In any event, the constructive effort is very high and the devices are consequently not only expensive but also susceptible to failure.
Conventionally, the holding device and the erecting member are disposed next to one another on the planetary part and are pivotable independently of one another. As a result, the different rotational motions of the holding device and of the erecting member as well as their mutual separation disadvantageously lead to relatively high dynamic loads acting on the planetary part. These loads produce irregular rotary motions, whose accommodation causes difficulties in structuring the planetary part, an increase in the amount of space required, and leads to the eccentric displacement of relatively large masses.
It is the underlying purpose of the invention to produce a device of the above-mentioned type which has a compact construction and which guarantees reliable transferring of the folded box to the transport device.
This object is achieved in a device of the above-mentioned type in that a first correcting rotary motion, defined by a first control curve, can be superimposed upon the holding device via a first gearing arrangement and a second correcting rotary motion, defined by a second control curve, can be superimposed upon the erecting member via a second gearing arrangement, wherein both gearing arrangements are disposed substantially coaxially with respect to one another.
In accordance with the invention, correcting rotary motions are defined by one independent control curve for each rotary motion of the holding device and of the erecting member, and are superimposed upon the respective rotary motion associated with rotation of the planetary part. This produces a corrected hypocycloid path which is optimally adjusted to the construction of the packaging machine.
To prevent the two gearing arrangements for the correcting rotary motion of the holding device and of the erecting member from producing large eccentric loads on the planetary part and thereby large imbalances during the rotary motion, the invention provides that, to the extent possible, the gearing arrangements are disposed coaxially with respect to each other. In this fashion, a transferring device can be produced which requires little space.
A preferred embodiment of the invention provides that the first gearing arrangement comprises a first correction shaft which indirectly engages the first control curve and which is rotated thereby and which drives, via a first gearing arrangement, a first drive shaft which is eccentrically disposed parallel thereto and which supports the holding device. The second gearing arrangement also comprises a second correction shaft which indirectly engages the second control curve and which is rotated thereby and which drives, via a second gearing arrangement, a second drive shaft which is eccentrically disposed parallel thereto and which bears the erecting member, wherein the two correction shafts and the two drive shafts are each coaxial with respect to one another. The coaxial arrangement of the drive shafts and of the correction shafts utilizes the construction space to an optimum degree and minimizes the eccentricities and associated additional dynamic loads of the transferring device.
The first correction shaft is preferably formed as a hollow shaft through which the second correction shaft penetrates. The second drive shaft may also be a hollow shaft through which the first drive shaft penetrates.
To change or adjust the correcting rotary motion if required, the sun axis is provided with a control disc which can preferably be replaced and in which the two control curves are formed. A further embodiment of the invention thereby provides that the two control curves are defined on opposing sides of the control disc to prevent mutual interference and to substantially free the course of the control curves.
Further details and features of the invention can be extracted from the following description of an embodiment with reference to the drawing.